Since each domain of explanations is defined by the criterion of validation used by the observer to accept a given reformulation of the praxis of living as an explanation of it, there are as many domains of explanations as criteria of acceptability for explanations an observer may use in his or her listening. At the same time, and as a result of this, each domain of explanations constitutes a domain of actions (and statements of actions in a domain of descriptions) that an observer considers in his or her reflections as legitimate actions for a particular domain of the praxis of living because they are supported by the explanations that he or she accepts in that domain. Moreover, and as I shall show later, since each domain of actions that are accepted as legitimate actions in a particular domain of the praxis of living by an observer is a domain of cognition in that domain, each domain of explanations, by specifying a domain of legitimate actions in the praxis of living of the observer, specifies a domain of cognition. Due to this, all observers that use the same criterion of validation for their explanations operate in cognitive domains that intersect in those aspects of their praxis of living specified by their common domains of explanations as domains of consensual co-ordinations of actions, and have their isomorphic domains of existence. Finally, whether an observer operates in one domain of explanations or in another depends on his or her preference (emotion of acceptance) for the basic premises that constitute the domain in which he or she operates. Accordingly, games, science, religions, political doctrines, philosophical systems, and ideologies in general are different domains of operational coherences in the praxis of living of the observer that he or she lives as different domains of explanations or as different domains of actions (and therefore of cognition), according to his or her operational preferences. Of these, I shall now only consider science - modern natural science - both because I am a scientist and because science plays a central role in the validations of knowledge in our western culture and, hence, in our explanations and understanding of social and ethical phenomena now in our cultural present.
We scientists like to explain the praxis of living, and the passion for explaining is the fundamental emotion that supports what we do as such. Furthermore, what is peculiar to modern scientists in general, and especially to modern natural scientists, as they do science, is their particular manner of listening for what they consider acceptable reformulations of the praxis of living, and their serious attempt to remain always consistent with it in their statements about what happens in their domains of experience. As a result, modern science is a peculiar domain of explanations and of derived statements about the praxis of living that is defined and constituted in the application by the observer in the particular criterion of validation of explanations - the criterion of validation of scientific explanations. Indeed, all those persons who accept, and consistently use, the criterion of validation of scientific explanations for the generation of their explanations, as well as for the validation of their statements in a particular domain, are scientists in that domain. Let me now present this criterion of validation and then reflect upon what I consider its significance per se, and for its application for the purpose of this article.
We modern natural scientists accept a given proposition as a scientific explanation of a particular situation of our praxis of living as observers (or phenomenon to be explained), only if it describes a mechanism that produces that situation or phenomenon as a consequence of its operation as one of four operational conditions that the observer can conjointly satisfy in his or her praxis of living. These four conditions are:
a) The specification of the phenomenon to be explained as a feature of the praxis of living of the observer through the description of what he or she must do to experience it.
b) The proposition in the praxis of living of the observer of a mechanism that as a consequence of its operation would give rise in him or her to the experience of the phenomenon to be explained.
c) The deduction from the mechanism proposed in (b) and of all the operational coherences that it entails in the praxis of living of the observer, of other phenomena as well as of the operations that the observer must do in his or her praxis of living to experience them.
d) The actual experience by the observer of those additional phenomena deduced in (c), as he or she performs in his or her praxis of living those operations that, according to what has also been deduced in (c), would be generated in it as he or she realises them.
When these four conditions are satisfied in the praxis of living of the observer, and only then, the mechanism proposed in (b) as a generative mechanism that gives rise as a consequence of its operation to the phenomenon specified in (a) becomes a scientific explanation of that phenomenon for the observer. Furthermore, the generative mechanism proposed in (b) remains, for an observer, as a scientific explanation of the phenomenon specified in (a) only as long as all the phenomena deduced in (c) are experienced by him or her according to the indications also deduced in (c). Therefore, scientists are only those observers who use the criterion of validation of scientific explanations for the validation of their explanations, and they do this by carefully avoiding confusing operational domains.
I call these four operational conditions the criteria of validation of scientific explanations because we modern natural scientists use them in the praxis of scientific research for the generation of scientific explanations. Indeed, what I say is that science as a domain of explanations and statements arises in the praxis of scientists through the application of the criterion of validation of explanations presented above, and not through the application of a criterion of falsification, as suggested by Popper. Let me now make some comments.
1) To the extent that science arises as an explanatory domain through the application of the criterion of validation of scientific explanations, science, as a domain of explanations and statements, is valid only in the community of observers (henceforth called standard observers) that accept and use for their explanations that particular criterion. In other words, science is constitutively a domain of reformulations of the praxis of living with elements of the praxis of living in a community of standard observers, and as such it is a consensual domain of co-ordinations of actions between the members of such a community. As a result of this, scientists can replace each other in the process of generating a scientific explanation. At the same time, it is this constitutive interchangeability of scientists that gives rise to the statement that scientific explanations must be corroborated by independent observers. Indeed, when two scientists do not coincide in their statements or explanations, it means that they belong to different consensual communities.
2) Since the criterion of validation of scientific explanations does not entail or require the supposition of an objective world independent of what the observer does, scientific explanations do not characterise, denote or reveal in an objective world independent of what the observer does. Due to this, as a domain of explanations and statements, as a domain of consensual co-ordinations of actions in a community of standard observers, science takes place as a system of combinations of explanations and statements in the praxis of living of standard observers that expand their praxis of living according to their operation with those combinations of explanations and statements in their praxis of living as members of a community of standard observers.
3) Since it is not measurement, quantification or prediction that constitutes science as a domain of explanations and statements but the application of the criterion of validation of scientific explanations by a standard observer in his or her praxis of living, a standard observer can do science in any domain of the praxis of living in which he or she applies this criterion.
4) Since the criterion of validation of scientific explanations validates as a scientific explanation a mechanism that generates the phenomenon to be explained as a consequence of its operation, the explanatory mechanism and the phenomenon to be explained necessarily belong to different and not intersecting phenomenal domains. Therefore, constitutively, a scientific explanation does not consist in a phenomenic world.
5) The operations that constitute the criterion of validation of scientific explanations are the same that we use in the operational validation of the praxis of our daily life as human beings. It follows from this that, in a strict operational sense, what distinguishes an observer in daily life from an observer as a scientist is the scientist's emotional orientation to explaining his or her consistency in using only the criterion of validation of scientific explanations for the system of explanations that he or she generates in his or her particular domain of explanatory concerns, and his or commitment to avoid confusing phenomenal domains in his or her generation of scientific explanations.
6) A structure determined system is a system in which all that happens happens as a structural change determined in it at every instant by its structure at that instant, regardless of whether this structural change arises in it in the flow of its own internal dynamics, or contingent on its interactions. This means that nothing external to a structure determined system can specify the structural changes that it undergoes as a consequence of an interaction. An external agent that interacts with a structure determined system can only trigger in it structural changes determined in it. The components, plus the static or dynamic relations between them that an observer distinguishes at any instant as composing a structure determined system, are the structure of that system. A dynamic structure determined system, that is, a structure determined system constituted as a system in continuous structural change, is a mechanism. In these circumstances, to claim that the criterion of validation of a scientific explanation is centred around the proposition of a mechanism that gives rise to the phenomenon to be explained as a consequence of its operation is to claim that science can only deal with structure determined systems. Or, in other words, to claim that a scientific explanation entails the propositions of a mechanism that generates the phenomenon to be explained, is to claim that the observer can propose scientific explanations only in those domains of operational coherences of his or her praxis of living in which he or she distinguishes structure determined systems.
7) Although the practice of science entails the application of the criterion of validation of scientific explanations, most scientists are not aware of the epistemological and ontological implications of what they do because for them science is a domain of practice and not a domain of reflections. Something similar happens to many philosophers that do not understand what takes place in science because for them science is a domain of reflections, and not a domain of practice. As a result, both of them usually follow the general trend of our western culture and a) accept scientific explanations as reductionist propositions under the implicit belief that they consist in expressing the phenomenon to be explained in more fundamental terms, and b) do not see the generative character of scientific explanations because they are under the implicit or explicit belief that the validity of scientific explanations rests on their direct or indirect reference to an objective reality independent of what the observer does. Finally, due to this usual blindness about what constitutes a scientific explanation in modern science, both scientists and philosophers frequently believe in our culture that to be objective in the practice of science and philosophy means that the statements or explanations that one makes as such are valid through their reference to an independent reality. In practice however, for an acting scientist to be objective only means not letting his or her desire for a particular outcome in his or her research to obscure his or impeccability as a generator of scientific explanations in the operational terms that I have presented above.
8) Together with the implicit or explicit assumption that scientific statements refer to an objective independent reality usually goes the implicit belief (and the emotion of certainty that supports it) that it is in principle possible to find for any dilemma of human life an objective (transcendental) argument that dissolves it, and whose reference to the real constitutively makes it undeniable and rationally valid. However, there is at the same time in our western culture a frequent doubt about the possibility that science may at all be able to explain certain features of the praxis of living like psychic and spiritual phenomena, precisely because of the mechanistic nature of scientific explanations and their assumed reductionistic character. What I have said above, however, shows that his manner of thinking entails a misunderstanding about scientific explanations that, for my purpose in this article, it is necessary to dispel. As I have said, scientific explanations are constitutively not reductionist. On the contrary. Since a scientific explanation is the proposition of a generative mechanism that gives rise as a consequence of its operation to the phenomenon to be explained in a different phenomenal domain than the one in which it takes place, a scientific explanation constitutes and validates the existence of completely different nonintersecting phenomenal domains that are intrinsically not reducible to each other. So, the mechanistic character of scientific explanations constitutively does not negate the possibility of a scientific explanation of psychic and spiritual phenomena. On the contrary, it opens the possibility to explain them as biological phenomena. Indeed, the mechanistic character of scientific explanations specifies that, in order to explain psychic and spiritual phenomena as biological phenomena, the observer must propose a generative mechanism that applies to him or herself as a living system giving rise to such phenomena as a consequence of its operation. As such a mechanism would give rise to psychic and spiritual phenomena as a consequence of its operation, it would not negate their particular experiential character because it would constitute the phenomenal domain in which they take place as a phenomenal domain that does not intersect with the phenomenal domain in which it takes place as a generative mechanism.
Einstein said on one occasion that scientific theories were free creations of the human mind. What I have said above about the criterion of validation of scientific explanations shows that this indeed has to be so. Both the phenomenon to be explained and the generative mechanism proposed are proposed by the observer in the flow of his or her praxis of living, and as such they happen to him, and he or she lives them as experiences that arise in him out of nowhere. In his or her actual living, the observer brings them forth a priori, even if afterwards he or she can construct rational justifications for them. Einstein also said that what marvelled him was that, even though scientific theories were free creations of the human mind, they could be used to explain the world. That this should be so is also apparent from the criterion of validation of scientific explanations. In fact, scientific explanations do not explain an independent world, they explain the experience of the observer, and that is the world that he or she lives.